.header{
    display: flex;
    height: 48px;
    line-height: 48px;
}
.header > div{
    width:200px;
}
.header >ul{
    display: flex;
    margin: 0;
    padding:0;
    list-style: none;
}
.tab_item{
    width:80px;
    text-align: center;
    position: relative;
}
.active >i{
    display: block;
    position: absolute;
    bottom:0;
    left:0;
    width:100%;
    height:2px;
    background-color: #fff;
    border-radius: 1px;
}